A Magnesium-Based Nanobiocomposite Processed By A Novel Technique Combining High Shear Solidification And Hot Extrusion.

BACKGROUND: Most of the currently available Mg-based biomaterials corrode too fast in the physiological environment, causing many problems including hydrogen bubble release and premature mechanical failure. It is commonly recognized that high biodegradation rate is the major factor limiting their clinical applications. Hence, the present research aims to develop a new magnesium (Mg)-based biomaterial with a controlled biodegradation rate.

METHODS: A magnesium-hydroxyapatite (Mg-1.61Zn-0.18Mn-0.5Ca/1HA) nanocomposite was developed by a novel technique which combines high shear solidification and hot extrusion, followed by heat treatment. The microstructure and biodegradation rate of the nanocomposite in HBSS Hanks' Balanced Salt Solution were assessed. Biodegradation behaviour was studied using electrochemical corrosion and immersion test. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the surface microstructure, biodegradation morphology and to analyse the biodegradation products.

RESULTS: Under the optimized procedure of high shear solidification, extrusion and heat treatment at 400 °C, the Mg-1.61Zn-0.18Mn-0.5Ca/1HA exhibited a satisfactory biodegradation rate of 0.12±0.04 mm/year.

CONCLUSION: This technology shows potential of breakthrough innovation in the manufacturing of Mg-based biomaterials with a decreased biodegradation rate.